Formation of polymeric films by surface-initiate polymerization and their applications to cell culture and biomimetic mineralization

Abstract

Surface-initiated polymerization is mostly useful to modify surfaces of solid substrates because of its advantages such as (1) the ability to control the film thickness by the concentration of monomers and reaction time, (2) the ability to control grafting densities of polymeric films by the surface coverage of initiators, (3) the ability to grow block copolymers in a controlled manner, (4) the possibility to be combined with micro/nanopatterning techniques, and (5) the better uniformity of the polymeric films on the surface of various solids. Polymeric films on substrates were formed by simple two steps in surface-initiated polymerization: Firstly, initiators for polymerization were immobilized on surfaces of substrates, and then, monomers were polymerized on surfaces. The polymers formed by surface-initiated polymerization on surface had brush-type structure and utilized in nano- and biotechnology. In this thesis, various polymers were formed on various substrates by surface-initiated polymerization, and then, utilized in field of cell culture and biomimetic mineralization. Chapter 2 describes procedures for formations of PNIPAAm polymeric films on surface of gold substrate and application of polymeric films to cell culture matrix. Thermoresponsive poly(N-isopropylacrylamide) (PNIPAAm) films were formed on gold substrates by a combination of formation of self-assembled monolayers terminating in bromoesters and surface-initiated, aqueous atom-transfer radical polymerization of N-isopropylacrylamide (NIPAAm). The polymerization was rapid and we successfully grew thick (>100 nm) PNIPAAm films. The PNIPAAm films were utilized for the applications to cell culture: NIH 3T3 fibroblasts were cultivated on the thermoresponsive PNIPAAm films and a preliminary study on the temperature dependency of cell attachment/detachment was performed. Chapter 3 describes formations of various gold nanparticle/PNIPAAm hybrids and their thermoresponsivenss. In this chapter, we in...